SATURDAY, May 31, 2014 (HealthDay News) -- A new oral drug called lenvatinib looks promising as a treatment for a type of thyroid cancer that resists standard radiation, according to a later-stage clinical trial.

"We are confident that, based on our findings, lenvatinib will eventually become a standard treatment for radioiodine-resistant thyroid cancer," said study lead author Dr. Martin Schlumberger, a professor of oncology at the University Paris Sud in Paris, France.

"As little as a year ago, this group of patients had no effective treatment options. It's remarkable that we now have two active drugs in this setting, both of them tyrosine kinase inhibitors," he added in a statement provided by the American Society of Clinical Oncology.

Eisai Inc., lenvatinib's manufacturer, supported the research. Findings from the study are scheduled to be presented Monday at the annual meeting of the American Society of Clinical Oncology in Chicago. Research presented at meetings is generally viewed as preliminary until it's published in a peer-reviewed journal.

An estimated 60,000 annual new cases of thyroid cancer are diagnosed in the United States. This research includes the most common subtype of thyroid cancer called "differentiated." These types of tumors can typically be cured with a combination of therapy and radiation treatment, but about 5 to 15 percent of patients develop resistance to the radiation treatment.

Another new drug, sorafenib, received federal approval last year to be used as a treatment for people with differentiated thyroid cancer. The drug now being studied, lenvatinib, works in a similar way.

In the new study, almost 400 people with advanced, radiation-resistant, differentiated thyroid cancer were given lenvatinib or a placebo. Tumors shrunk in 65 percent of the patients who took the drug compared to 3 percent of those who took the placebo; those who took the drug went for an average of 18 months without disease progression, compared to just under four months for those who took the placebo.

The researchers don't know yet how long the patients will survive on average.

"The progress we're seeing with targeted agents for uncommon cancers is encouraging," said oncologist Dr. Gregory Masters in a statement provided by the American Society of Clinical Oncology. "Patients with differentiated thyroid cancer have historically had limited options when the disease progresses despite radioactive iodine therapy. Now this new drug, lenvatinib, offers an effective option with reasonable side effects and can help patients live longer before the disease worsens."